d2db661021
It seems that a margin for stack overflow checking is added to top of a kernel stack but is not added to IRQ and exception stacks in stack_overflow_check(). Therefore, the overflows of IRQ and exception stacks are always detected only after they actually occurred and data corruption might occur due to them. This patch adds the margin to top of IRQ and exception stacks as well as a kernel stack to enhance reliability. Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20111207082910.9847.3359.stgit@ltc219.sdl.hitachi.co.jp [ removed the #undef - we typically don't do that for uncommon names ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
/*
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* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
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*
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* This file contains the lowest level x86_64-specific interrupt
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* entry and irq statistics code. All the remaining irq logic is
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* done by the generic kernel/irq/ code and in the
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* x86_64-specific irq controller code. (e.g. i8259.c and
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* io_apic.c.)
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*/
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#include <linux/kernel_stat.h>
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#include <linux/interrupt.h>
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#include <linux/seq_file.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/ftrace.h>
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#include <linux/uaccess.h>
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#include <linux/smp.h>
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#include <asm/io_apic.h>
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#include <asm/idle.h>
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#include <asm/apic.h>
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DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
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EXPORT_PER_CPU_SYMBOL(irq_stat);
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DEFINE_PER_CPU(struct pt_regs *, irq_regs);
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EXPORT_PER_CPU_SYMBOL(irq_regs);
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int sysctl_panic_on_stackoverflow;
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/*
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* Probabilistic stack overflow check:
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*
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* Only check the stack in process context, because everything else
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* runs on the big interrupt stacks. Checking reliably is too expensive,
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* so we just check from interrupts.
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*/
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static inline void stack_overflow_check(struct pt_regs *regs)
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{
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#ifdef CONFIG_DEBUG_STACKOVERFLOW
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#define STACK_TOP_MARGIN 128
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struct orig_ist *oist;
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u64 irq_stack_top, irq_stack_bottom;
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u64 estack_top, estack_bottom;
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u64 curbase = (u64)task_stack_page(current);
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if (user_mode_vm(regs))
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return;
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if (regs->sp >= curbase + sizeof(struct thread_info) +
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sizeof(struct pt_regs) + STACK_TOP_MARGIN &&
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regs->sp <= curbase + THREAD_SIZE)
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return;
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irq_stack_top = (u64)__get_cpu_var(irq_stack_union.irq_stack) +
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STACK_TOP_MARGIN;
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irq_stack_bottom = (u64)__get_cpu_var(irq_stack_ptr);
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if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom)
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return;
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oist = &__get_cpu_var(orig_ist);
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estack_top = (u64)oist->ist[0] - EXCEPTION_STKSZ + STACK_TOP_MARGIN;
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estack_bottom = (u64)oist->ist[N_EXCEPTION_STACKS - 1];
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if (regs->sp >= estack_top && regs->sp <= estack_bottom)
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return;
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WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx)\n",
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current->comm, curbase, regs->sp,
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irq_stack_top, irq_stack_bottom,
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estack_top, estack_bottom);
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if (sysctl_panic_on_stackoverflow)
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panic("low stack detected by irq handler - check messages\n");
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#endif
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}
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bool handle_irq(unsigned irq, struct pt_regs *regs)
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{
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struct irq_desc *desc;
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stack_overflow_check(regs);
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desc = irq_to_desc(irq);
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if (unlikely(!desc))
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return false;
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generic_handle_irq_desc(irq, desc);
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return true;
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}
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extern void call_softirq(void);
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asmlinkage void do_softirq(void)
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{
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__u32 pending;
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unsigned long flags;
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if (in_interrupt())
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return;
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local_irq_save(flags);
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pending = local_softirq_pending();
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/* Switch to interrupt stack */
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if (pending) {
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call_softirq();
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WARN_ON_ONCE(softirq_count());
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}
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local_irq_restore(flags);
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}
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